Generally, when a tooth falls out, a denture is put in a mouth or a bridge procedure for covering a space of the fallen tooth with a metal or the like is performed, by using surrounding teeth as supports. However, according to such surgical procedures, a denture and a bridged artificial tooth are weak for chewing and may adversely affect surrounding teeth. Thus, an implant procedure has appeared as one of developed dental procedures. According to the implant procedure, an artificial tooth root is formed in an alveolar bone and is combined to an artificial tooth that is a final prosthetic appliance manufactured similar to an actual tooth, and thus a patient obtains an effect of using an actual tooth.
According to the implant procedure, an implant groove is formed on an alveolar bone where a tooth has fallen out by using a tool, such as a drill, so as to implant a fixture, and tapping is performed as a selective operation for the fixture to be strongly implanted in the implant groove. After implanting the fixture in the implant groove, a cover screw is locked to the fixture and gums are sutured to prevent impurities from penetrating into the fixture, thereby completing a primary surgery. Then, a secondary surgery is performed after about 3 to 6 months by cutting the sutured gums to remove the cover screw from the fixture, considering a type of abutment to be locked, and then selecting and locking a healing abutment to the fixture. Here, the healing abutment is locked so that the gums are neatly formed on the fixture before locking the abutment to the fixture. After the gums are formed suitably for locking the abutment after about 2 to 3 weeks, the healing abutment is removed and then the abutment is combined to the fixture. Then, the implant procedure is completed by combining a final prosthetic appliance having a shape of a natural tooth to a top of the abutment.
According to such a general implant procedure, when a part of the alveolar bone is lost and it is difficult to sufficiently support the fixture only by using the remaining alveolar bone, a surgical procedure of filling a bone graft in the lost part such that the bone graft operates as a new alveolar bone is additionally performed. In other words, the surgical procedure of generating the lost part of the alveolar bone is performed, which is called guided bone regeneration (GBR). In order to perform the GBR, first, the fixture is inserted into the alveolar bone and the bone graft, such as an artificial bone or autogenous bone, is filled in the lost part. Then, the fixture is covered by a dental membrane so that the filled bone graft maintains a required shape. Next, the dental membrane is fixed to a required location by using a predetermined cover member.
Such a conventional technology is disclosed in U.S. Pat. No. 6,171,106 about “Cover Screw for Dental Implant”, wherein FIG. 1 is a representative drawing. Here, as shown in FIG. 1, a male screw 3a of a main body 3 is screwed to a threaded hole 1a of an implant fixture 1 implanted to an alveolar bone B, and a barrier membrane 5 is mounted on a face 3b to cover a partial top of the alveolar bone B. A male screw 4c of a membrane fixing screw 4 is screwed to a threaded hole 3c of the main body 3, wherein the barrier membrane 5 is inserted and fixed therebetween. Meanwhile, a gingival G is disposed on the barrier membrane 5 to cover the barrier membrane 5 so as to prevent external impurities or pollutants from penetrating into the barrier membrane 5 during GBR.
However, a dental membrane according to such a conventional technology has the following problems.
First, a fixing screw is disposed on the dental membrane according to the conventional technology, and a space is formed on the top of the dental membrane due to the fixing screw. The space may have a size corresponding to a height of the fixing screw. For example, when the fixing screw is thick, the space may be big, and when the fixing screw is thin, the space may be small. If the space is generated as such, undesired impurities or foreign matters may be filled in the space, and thus an inside of a gingiva may be contaminated. Such contamination interferes with osseointegration, thereby increasing a bone regeneration time or causing osteolysis if worse.
In addition, according to the dental membrane of the conventional technology, it is not easy to form an alveolar process that bulges in an arch shape around an implanted tooth. Generally, an alveolar process bulges around a tooth and commonly exists in a general tooth. A gingiva having a similar shape as the alveolar process is formed on the alveolar process, and the gingiva formed around an artificial tooth in 3-dimensions arouses an aesthetic sense of a viewer. Meanwhile, the alveolar process has a bulging shape, but since a conventional dental membrane has a simple flat or bended shape, it is not easy to form the alveolar process.
On the other hand, it was easy to make a space in a bone deficient region, i.e., increase a bone horizontally and vertically, by using titanium, which is a nonabsorbent material compared to other materials. However, in an anterior region where an aesthetic sense is required, not only is the increasing of the bone important, but the shape of the increased bone is also important. In other words, for the aesthetic sense of the anterior region, a gingival papilla (a bulging portion formed between teeth or around a tooth) needs to be formed, but it is difficult for an operator to form the gingival papilla via bending and trimming at the spot of dental treatment by using the conventional dental membrane.
In detail, in order to obtain a satisfactory bone increasing effect while realizing a gingival papilla, an additional procedure of grinding or trimming an alveolar bone is required. However, such an additional procedure is not only difficult to be performed, but also burdens a patient and an operator in terms of time and expense.